Rotary expansion engine



May 19, 1953 G. E. MALLlNcKRoDT ROTARY EXPANSION ENGINE Filed NOV. 8, 1950 l 4 Sheets-Sheet l TSC l alla/Y N 24 ...J Il

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May 19, 1953 G. E. MALLlNcKRoDT 2,538,880

ROTARY EXPANSIONENGINE Filed Nov. e, 195o 4 'sneetsfsheet 2 `Maly 19, 1953 G. E. MALLlNc/KRODT 2,638,880

`ROTARY EXPANSION ENGINEl Filed Nov. a, 195o 4 sheets-sheets FIG .7. A

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235 al zal 33 (CG 256 L y 233 as GG\ 235 May 19, 1953 G. E. MALLlNcKRoDT 2,638,880

ROTARY EXPANSION ENGINE Filed'Nov.' s', 195o 4 sheets-sheet 4 Patented May 19, 195.3

UNITED es.

25638,880 RGTARYEXPANSIONENG'INE lGeorgeE; 4Mallinckrodt, 9St. YI.1ouis,.l\/Io. "ApplicationiNovember 8, 1950,'1SerialiNoi.194;599 izolaims (omas-11) This invention relates. to' rotary. expansion. engines capable of operating with 'expansivegaseous or vapor mediums such .as hydrocarbon .mixtures, air, steam, etc., .and .employing 'multiple rotors having opposed` pistons alternately. positioned ina-toroidal cylinder. 'It isfan rr-iprovement upon ithecon'struction disclosed inf-United States Patent 2,373,791, dated .April 17,1945, and upon the construction disclosed in my copending United .States .patent .application ',Serial '.No. 183,846, filed September 8,. 1950, foi- Rotary "Expansion Engine.

Briefly, the invention consists .in means for improving theperformance of a rotary engine of the stated classby use .of movable-rotorweights which improve-the -modefof transfer. ofmomentum from one rotor to another. .Briy vfthe movable weights are associated4 with .the respective rotors of the machine .and are. so `arranged that during a compression `event sufficient velocity is conserved in each rotor. so-that itv may-.positively7 reach -a required locking position. This is accomplished .by `preventing transfer-.of `all energy from one rotoiav as-.it Iadvances-upon .the other during the compression event. Theun transferred energy causesthe one. rotor to `follow the other rotor suiiiciently to reach the-locking position, which position is beyond-that which could -be attained without the-weights. Other improvements .and advantages will vappear below.

lThe invention comprises the elements and combinations of "elements, lfeaturesv ofconstruction, and arrangements of parts which will-be exemplied in the structures lhereinafter -.de scribed, and the scope of the application` of .which will belindicated in the following claims.

Inthe accompanying drawingsf-in-which several of various .possible embodiments` of the rinvention are illustrated,

Fig. 1 is an external ViewV ofone form of the invention;

Fig. 2 i-s a longitudinal section taken.1on 1ine 2 2 ofvFig.- 1;.

Fig.y 3 isa crosssection taken on line3--3 of Fig. 2, showing certain piston-midpositions;

Fig. 4 is a cross section-tal en on line-Ai of Fig. 2, illustrating one -of two identical lone-way or reverse locking clutches;

Fig. 5 `is lan exploded isometric l.View of `rtwo rotors removed-from the engine;

Fig. 6 is an kisometric detail, ronfanenlarged scale, illustrating certain piston seals;

Figs. "7-9 are diagrammaticfviews .of -the-;pis- Y* tons -at various positions 'developed throughout ar cycle of action 'beginning-with-theposition shown -in Fig. 2; and,

1rig. 10 is-a crcsssection taken-online #Q -l0 of Fig. 2.

Similar reierencecharacters indicate correspending parts throughout-thaseveral l.views of the drawings.

Referring-now Jmore particularly to-Eigsv @-1-6 there is shownat r'iu'rneral` Iaoase-'or-i-rame consisting of a drum 3 and end members 5, the

latteroontaining Vair. passages. J. .The case Lsuppo'rts a rotary. power shaft@ .in end bearings-l1. Supported in a rotary manner is .a rotor Aarourid the. 4lft .endv..of power. 'shaft 9 ...and .a i rotor'l'B aroundthe 'right endoi .power shafts. RotorA is carried.upon..bearings.1.3 within ringslMand l5, both of which `rings .are attached. within `rotor A. `,Rotor`.l5x cairieduponbearings Irings '1,8 tand' 1.9,. both oi'swhich yrings are .attached withimrotorjs. ijllywhcels. 21.1 and 93.r .ares keyed tothel rotors .Aand.B, respectively.

"Rotor A carries .oppositelylocated plateype pistons'W and X; and rotor B carriesioppositely .located p1ate-.typerpistonsiY .and .Z .(see.1iig..5) hepistons-`X,'YanlZ revolve in atorcidal cylinder 4C of rectangular .crosssection .cylinderC Iis comprisedby.. anfouterjsleeve- 2 5.1911 the' exterior f which are air-cooling ns 2.1. Water coolingmaype .used...at. .thisv point. .if.,.de sired. 'lBolted to. lthe` sleevel. are end plates I2,9. l,audit .l .through which. extend..,thefladjacent endsy 31 yrandil. .oi .'the. rotors: Landil '.Ivfhese adjacent. rotor .ends-.3.75. and '39 form `.the inside suiace ofthacylinder.

"The rotors .Ag V, "dB move relativelyandthekre.- forean' intermediatabrass or likesealing ringri is employed in .connectionwith abuttinggfroo-yes 3.5. sealing ring- A Lis employedhetween rotor Afandgplate'fl, and afsealin'g ring is .employed between.- rotor'LBk and. y.plate .31. The .grooves for this, *purposen rotors Aand.. E gare shown. at arid/w51, respectively, in' Fig. :5. 4The .assemblyof p a'rts' .25," ,Z9 and $.31 of .,cylinder. C` `.iss'imported upon v intelm'allugs .A9-v. carried. .wthin ..the caselI ThegpistonsWandX.extend .from end l of rotor Aovergtne emita. of. retenue. rhepisins irland Z extendlfrom.. endof rotor TB .oi/Teri. the end? ,3,1 ef. Vrotor A. Thus .jl;1 1e `pistons W.....and.X4 .on .the onehand, aniY and'zon .the otherhandgin-terdigitate alternately. `wi'thinthe cylinder-Cito .track one 'another .in said .cy1inder-..under relative: .rme-

tionslfftherotors A andfi. ..In.orderftoproyide l a gas-"or vapor-tight seal between.,eachgpiston and. rthe Wa1ls-, of.cylinder C.- :the ypistonsare grooved .as shown .at iL-.for .the .reception of. slidable.' L-shaped sealingsmembersf `(see Figs..5 andl). 'jI'hese imembers were.providedwith slidingmo'r-tises 55 to allowseparatng movements under'. action of. an.internal expansion. springf'l, oneibeing 'employed forV eachpair osealingrme-Ilbers'. lOnefpair of -:members :and a spring; are carriedin eachggrooveil. 'lfheisealing members' are' .not shown .in,1iig., 5. but they are# shown irifFigs. 2an'd'6. Y

Adriving.. connection isaiiorded between -both of 'the rotorsA. and `-Bon the,-one.hand,.and the shaft 9 ,on the.. other-handy byr'fmeans 0f :differential gearing...indicated generally at D. 'ZTh-is gearingconsists. of a bevel'. gear@ 59 i rigidly connectedfwith vrotor'A'iby bolting to ring' Il 5. j Itfalso -has.a-beve1.gear.6 I` rigidly connected `with-:rotor B-by-boltingato' ring 1.9. Inserted'. at rightangles in shaft 9i-isi-afpin63;fwhichzcarries rotary. .pinions v6 5, eachiofiwhich mesheszwiftlrgearsiBS and 6I. If rotor A is held stationary and rotor B advances, gear 59 will be stationary and gear 5| will be rotated with rotor B. The pinions 65 Will then be rolled on gear 59 by gear 6| and w111 drive the shaft 9 at half the speed of the rotor B. On the other hand, if rotor B is stationary and rotor A advances, gear 6| will be stationary and gear 59 will be rotated with rotor A. The pinions 65 will be rolled ongear 6| by gear 59 and will drive the shaft 9 at half the speed of the rotor A. I

The purpose of the differential gearing D is under such conditions to deliver an angular velocity to the shaft 9 which is the average of the angular velocities of rotors A and B. This angular velocity will be one-half of the maximum angular velocity of either rotor A or B when the other is stationary. When either rotor A or B decelerates, the other is accelerated (as will appear) but their average angular velocity will be delivered to shaft 9. The angular velocity of shaft 9 will be substantially constant when connected to a device having a substantial moment of inertia, such as an electrical generator, flywheel or the like.

While a bevel gear type .of diierential gearing is shown, it will be understood that equivalent differential gearing may be carried out with other than bevel gears, as for example, an all-spur gear differential.

In order to conne the movements of rotors let pipe 91 in which is a manual starting control valve 99. The pipe 91 connects with an air inlet port IUI in plate 29. The location of port IUI is also shown by dotted lines in Fig. 3. The purpose of this arrangement is to allow the machine to build up pressure in the tank 89 (through 85, 8l, 9|, 93 and 95) and to use this pressure for starting or running purposes at port IUI, as will appear. Near the air inlet port IBI is an ignition plug |03 which is of the variety which maintains a constant igniting spark or temperature. For example, it may be a constantly arcing plug, a glow plug, or a so-called hot bulb, this plug at all times maintaining an igniting temperature.

The point of departure for the present invention from that shown in my said application Serial No. 183,846 relates to the flywheels 2| and 23. These in a simpler manner perform certain momentum transfer functions between the identical rotors A and B which were performed by an accumulator system described in said application.

A and B to one direction (counterclockwise; Figs. i. :i

3 and '7-9), each is provided with a reverse locking ratchet or clutch, the ratchet for rotor A being indicated in general at E, and the ratchet for rotor B being indicated in general at F. While any of various forms of ratchets or clutches each sleeve are 180 apart. The long extent of the spiral springs 61, when lubricant is contained within the sleeve 15, renders their operation quiet, and the springs are made heavy enough to withstand the reactive forces during power operation.

Since each flywheel and attached parts are identical to the other, it will be necessary to describe only one, the same reference characters for parts being used on each except that the parts for the flywheel 2| on rotor A will be primed. Thus the ilywheel 23 for rotor B comprises a ring 221 keyed to the rotor B, The ring is slotted at two opposite points, as shown at 229. The slots extend partway into the supporting rotor. In each slot is a swinging weight 23|, carried pivotally on a pin 233. As shown in Fig. 10, each weight 23| may swing from an inner position to an extended position, which has the effect of increasing the effective moment of inertia of the rotary parts with which the weights are connected, i. e., in this case the moment of inertia of the respective flywheel 23. and rotor B, including its pistons Y and Z. Each set of weights is preferably placed approximately in the plane of its rotor pistons but other positions are satisfactory in this re- Cross reference is here made to my copending si application Serial No. 325,083, filed December 10, 1952 for Ratchet, containing claims directed to the ratchet per se.

Referring t0 Figs. 1 3, numeral 11 indicates a suction port having an inlet passage 19 leading from a carburetor, mixing valve or other fuelpreparing device (not shown, since any suitable carburetor or the like may be used for internal combustion operation with gasoline, alcohol or the like). dotted lines in Fig. 3. It is actually in plate 3|, which is ahead of the Fig. 3 section. At numeral 8l is shown an exhaust port with which is connected an arcuate pressure-release channel 83,

The position of port is shown by sunk into the inner face of the ring 29. The exspect. Each weight 23| is provided with a front surface 235 which upon forward swing engages the bottom of its slot 229. This limits its forward swinging movement relatively to its ywheel to a position in which the moment of inertia of its connected rotary system is a maximum. Each weight 23| also has a rear surface 23E which upon rearward swing engages the bottom of its slot 229. The terms forward and rearward are relative to the rotor movement.

The starting operation on air is as follows, assuming that the tank 89 is initially charged with pressure, the valve 99 has been opened, the piston Z has reached the point in its power stroke shown in Fig. 3, and piston W is reverse locked at the top by action of the reverse locking ratchet E:

Air flows through pipe 9'? to port IBI. This accelerates the piston Z, forcing it to its position shown in Fig. 3.

Piston Y is at this vtime receding from the inlet or suction port 11 and, being blocked off from exhaust port 8| by piston X, draws in a combustible charge. Any spent charge from a previous cycle of operation is pushed out of the exhaust 8| ahead of piston Z. The charge ahead of piston Y is compressed toward piston W. The locking of pistons W and X is performed by the expansive action of the charge between pistons W and Z, tending to push pistons W and X clockwise. However, pistons W and X are blocked by reason of clutch E being in the locked position shown in Fig. 4.

As piston Y approaches piston W, the intervening charge is compressed, a small amount being released-through gport'-.afn'df needle' valveti to maintain the 'pressure'iin" tankf-St. lThe' needle valvel is adjusted to preventa'iarge amoantoi charge being usedor this-"prpose -fiihisat'tion isillustrated =in"-Fig.`7. 'The' WelghtsfI-fland 23 I are yall out in the'pos'itions iparts shown ainliig. 7. In the `case-oirotor Bfthe weights23-'Iare'1out in this figure because--th'isirotowhas attanedfia substantial angular 1 velocity Awhich 'ith-rows the weights out. In Arntn'ling -outthey havef-gradualiy brought their surfaces? 235' againstl the bottoms of seats 228,-=\vhioh=actas stops. vIn'tliefeasetof rotorl A, asf' it comes toa `stop, its Weights 23| are foutfby reason ofthefact that'thisrotorlhas decelerated from afrnaximum Yangulary velocity'iin coming" to its locked position. 'Thereafter-these weights may move inward.

-A short while after -thefFgff AAposi-tion;` piston Z crosses -port Stand-begins to release' the-working expansion'ip-ressure. @This releases '-pistonsf-W and X. The rotorBi-bythis-time `ihas-attained a substantial angular 4momentum 4(orlflififietic energy). Upon release Iof pressure' between pistons -W and `Z, *this angular momentum (kinetic energy) is 'transferr'edf'from rdtor'fB- to rotor A (througlithe compressive charge between pistons-W and Y). vThis 'isinthenaturenfa collision event -acting "through *the interposed compressive charge, instead -of '-by lii-rect contact between pistonsW-and-Y. vPistorrW'then gmoves to the positionfsho-wn in'F-igif. VAtl this moment, due to theacceleratiomf the rotor Al carrying pistons W` annif-X, theV weights*23l rotate 'backward to their'-innermosvpositions. l"Il'rns"`t-he moment lof inertia :of the rotor A -becomes smaller, whereas vthat of rotor-B remainsf-atf-its maximum due' toits weights'- 23 I 'being out," vas shoWnin-Figf. =Hencefthe`moment of inertia of the parts connected "Withrotor/Aris l'smaller than that of thel partsfconnectedwith rotor B, and the formercannot -absor'bf'all off the angular momentum of thelatter. Sincethelatter l(rotor B) cannot transfer 4all of itsangular' momentum to the rotor A, the rotonBWillnot'be completely stopped and it will'fdllow the rotor A untilS the piston'Y assumes `the locking positioirshownin Fig. 9. 'Without this*fea-ture"thev colliding piston Y could never assume thev position 'of pistonW collided with. A"Piston Y -is ithenstopped *and locked by expansion -of lthe charge between pistons W Aand vY, ignition ioccurringiat vthis time. Piston W then accelerates'and-weightsV 23 I start to swing out'agai-n (Fig. 9). f the moments of inertia of both rotors were-thesarnein'thepositions of lp-artssl'iovm inlig.*iL-theA trailing rotor B could notv assume-the initially locked-position of the rotor A, particularlyA under-Triest eilicient conditions of compression. This is because 'under such conditions' the tendency would be for rotor B to transmit substantially lall of its kinetic energy toA rotor "-A, thus-i'stopping"rotor B before its reversed locking position is reached. Butby means of this invention, during the'compression event the trailing rotor has 'a moment' of 'inertia relatively Aineizcess 'of' that of'the leading rotor. Hence'the' leading vrotorcannot accept all'o'f this momentum and thettrailingrotor with 'its'remaining'rnomentum will move ahead into the reverse locking position i It is ysto be observed that in identical ,positions of their Weights the two rotorsi'have' equal"'moments of inertia, but that :thefone in which theiw'eights are outermost at anylinstanthas the relatively greater moment of inertia.

At the stage of events shown in Fig. 9, the

piston W haslancovered,therein-inlet 'gpc'rtiiul ancheJ l fresh chargei oft.' rf introduced: .and4 the cycle ris i repeated llwithrotors MA- and 2B 1 interchanged in positions. At this time rotorlBis locke'diagainst 'backretat'ionlby clutch This state of alai-rslcontinues@with Athe ldevice operatingv essentially :asian y airl engine,- untiif the 'mixture lintiroduced 'in :port i 7 T reaches ".alconcentration Wherei-nlunder'ffthe S cyclic-1 action -above idescribed; the-ignition plug. 1103 `ignites thel charges andfthentheiair naybe turned ofi vatfvalve B9. 'ifnefoperationtwillfthenicontinueautomatically, encepti that y the charges '-'betweenl pistons-.asl they cross l the -fj'ort E10 I f are explosive, f-xand i as .these chargesiare -brongfhtoverltha plug? 1463,; they- `efrplode mithrexpansionaetion'.as already des'crib'ed.

rIEnfvi'evv ofi thewabovef it iwi-ll 1='be` seen thatLthe deviceratiill: operate -vcontinuous'ly' eithenas Lanfair engi-ne if no carburetor? isJusedk on-Lp-ipe 19,- loraas 1 aniinternallcombustionfenginevafter air starting hasllbeen accomplished themannenabove .indi-A cated; assumingthecarburetor to be-.attachedito sai-d Apipe -I 19.

finned-invention may'dieflep'itcknfiized;l .i-nlthis;- that each leading rotor when it leaves the locke'dfpc'sis tion 'lhas its? moinentflof inertia reduced fautomatiealflyzduetthel invslvvingi-ngi ofits Weigh-ts andere-.angular 1 acceleration; .whereasvrthe jother trailing rotenLiniapproachingithe flockedi :position behind theleading rotor lhasihadiitsemgular;

momentum increased by reason of the oiltxvaifd positions of its weightsl reached'viny responseto centrifugal forces 7loneurring :during :maximum angular velocity. 'iThe iutwardspositions -a-remaintained lduningldeceleration, Willich loccurs untilthe reverse lockingposition is'reaehed. IFIYhe inward positions are-'lattainedupon acceleration fromvvthe: lockingzlpos'itionfollowed fbyf agrari-ual outward movement `asithepveloeity increases. @It will beolearsiomlthei above that it -isfsnillo'ient for vcarrying foutthe importanti features =o the invention -i that tthe `imoment of inertia of 1 the rotary .i system zvvhich. advances toward vcollision shall beilarger `1 relative to A4the :movement -of inertianf the:.systemf which recedes therefrom.

YThe centers offlgravityi ofallwweights-aref :nidicated -at-,GG. Whenfa pairbof fiweighs is-linward, asfis-` the=.casel'iof .iwe'ights 5231 in L Ewig# 8, #their centers of'` gravity arelinsideof '.atangent iT-to the :circulartrajectory-of therespective pivot fpin 233. The vreverse Imomentfthusaapplied f--to -fthe Weights -as ctheyswing @inward l (under angular acceleration of their supporting lywheeDhl-ninimises percussion(-lwith-l the'` bottoms .fwoff theincontaining. slots. .Percussion abetween surfaces 2 3 5 and ythe bottoms-:offtries-slots :isxminimiaedby reason of the;gradualoutward;.movementsotthe Weights as their frespective .l rotors accelerate. Moreover thecenterof gravity .CGfof-each weight' in -the: outward .lpositioncloselto -a line L. 4passM ing through thef'rotor center 4andthe 1 `pivot of the weight r(seeiig. 2 '7.) fIhisfact :alsoL tends yto minimize percussion .euponf the?. outward lsvf'i-ng ci each Weight.

The term"inert;ia mechanism as 'usedherein refers i0-n1lyme3fn -by which thefzxrrromentoi inertiaof each rotary systemherein :described iscaused to be relativelmgreaterthan that of wthe other. during` ther period-thatsuch system. over takes the other" upon collision.

In view of the above/it will be seen thatthe several objects of the invention are achieved and othenadvantageousresults attained. *l

many-changesoouldvbemade in the above constructions Without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a rotary engine a toroidal cylinder, relatively movable pistons in the cylinder successively passing in the same direction a predetermined reverse locking position prior to an expansion event, means responsive to expansion for successively reverse locking the pistons as they reach said position, each succeeding piston compressing a charge against a preceding piston when the latter is reverse locked, said compressed charge being adapted to move the reverse locked piston from said locking position after said expansion event has substantially progressed, relatively movable rotors carrying theY respective pistons to and from the locking position, and centrifugal apparatus on each rotor responsive to rotor speed temporarily to increase the moment of inertia of the respective rotor and its connected parts over the moment of inertia of the other rotor and its connected parts, as a piston of the former approaches a reverse locking position.

2. Apparatus made according to claim 1, wherein each centrifugal apparatus is also responsive to its rotor acceleration to move inward to decrease the moment of inertia of its rotor as its piston proceeds from said reverse locking position.

3. In a rotary engine a frame, a rotary power shaft, a toroidal cylinder attached to said frame and surrounding -a center line passing through said shaft, rotors surrounding said center line being relatively movable in a given direction, said rotors including pistons respectively attached to the rotors and positioned for relative movement in said cylinder, a reverse locking clutch means operative between each rotor and the frame, means connecting both rotors with the shaft adapted to drive the latter, apparatus connected with each rotor comprising a movable part responsive to a rotor deceleration temporarily to assume a position in said apparatus increasing the moment of inertia of the respective rotor as one of its pistons approaches a reverse locking position, said apparatus being adapted in response to acceleration of its respective rotor to move said part to another position reducing the moment of inertia of the rotor as said piston proceeds from said reverse locking position.

4. In a rotary engine a toroidal cylinder, relatively movable pairs of pistons in the cylinder successively passing a predetermined reverse locking position, means for successively reverse locking the pistons as they reach said position and for unlocking them thereafter, succeeding pistons compressing fresh charges against pre ceding pistons when reverse locked, said fresh charges subsequently movingthe reverse locked pistons, rotors carrying the respective pairs of pistons, and at least one movable weight on each rotor adapted in response to relatively large angular velocity of the respective rotor to move forward through an arc from an inner position to an outerl position so as temporarily to increase the moment of inertia of the respective rotor as one of its pistons approaches the reverse locking position.

5. Apparatus made according to claim 4, wherein each weight is adapted in response to Yangular acceleration of its respective rotor to move inward and backward to decrease the moment of inertia of its rotor as one of its pistons recedes from said reverse locking position.

6. Apparatus made according to claim- 4, wherein each weight is pivoted, and wherein there are stops associated with the weights to limit their pivotal movements.

7. Apparatus made according to claim 6, wherein the center of gravity of each weight is arranged when the Weight is inward to lie within a line tangent to the trajectory of its pivot.

8. Apparatus made according to claim 6, wherein the center of gravity of each weight is f arranged to lie close to a line passing through its rotor center and the pivot of the weight when the weight is in its outer position, and wherein said center of gravity of each weight is arranged when the weight is inward to lie within a line tangent to the trajectory of its pivot.

9. A rotary piston engine comprisingV two cooperating rotary systems, pistons for effecting resilient compression events between them, wherein alternately one system advances upon the other to effect such an event and the other system recedes, an inertia mechanism on each system responsive to the occurrence of such an event, the mechanism being adapted momentarily to increase the moment of inertia of a system in response to its advance upon compression, said mechanism also being adapted to decrease the moment of inertia of a system in response to its recession from compression.

10. Rotary apparatus comprising at least two cooperating rotary systems, wherein alternately each system advances upon the other to effect a collision event, an inertia mechanism on each system responsive to the occurrence of the collision event to increase the moment of inertia of the system which -advances toward the collision and to decrease the moment of inertia of the system which recedes therefrom.

11. Rotary apparatus comprising at least two cooperating rotary systems, wherein alternately each system advances upon the other to effect a collision event, an inertia mechanism on each system responsive to the occurrence of the collision event to increase the moment of inertia of the system which advances toward the collision and to decrease the moment of inertia of the v system which recedes therefrom, and reverse locking means operative during the collision process adapted to prevent reverse movement of the advancing system.

12. Rotary apparatus comprising an assembly 1 of at least two cooperating rotary systems,

wherein alternately each system advances upon the other to eect a collision event, means forming part of the assembly operative during the occurrence of the collision event adapted a1- tern-ately to make the moment of inertia of one system larger relative to the other as said one system advances toward the other and the other recedes therefrom, and reverse locking means operative during the collision process adapted to prevent reverse movement of the advancing system.

GEORGE E. MAILINCIZRODT.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,904,892 Trube Apr. 18, 1933 

